Musannaf Ibn Abi Shayba 9:1769

Waki’ narrated to us, from Zakariyya, who said: Umayyah narrated to me, she said: I used to adorn the brides in Medina. So I asked Aisha about henna (dyeing), and she said: "There is no harm in it, as long as there is no engraving (or patterns) in it."